November-December 2008

Saving the San Pedro River: Science, Collaboration, and Water Sustainability in Arizona

by George Saliba and Katharine L. Jacobs

The San Pedro River in southeastern Arizona went dry for the first time in recorded history in the summer of 2005 at the Charleston Gauge and was nearly dry again in 2006. These events raised alarm among conservationists and water managers, who fear for the future of the river. On the other extreme are those who do not support protecting the river, such as the city councilman of Sierra Vista who declared in 1997, “All right, there may be 500 species of wildlife found along the San Pedro. My response is so what? What benefit do these animals have for humans? We are the ones who rule supreme, and if a plant or animal can’t adapt to our needs, then it’s too bad.” However, people are also endangered by a water shortage: if the San Pedro River goes from perennial to intermittent flow, loss of species and biodiversity will occur, as will threats of litigation from environmental groups under the Endangered Species Act. Litigation could lead to a reduction or, in a less likely scenario, closure of the region’s largest economic driver and primary stressor on the area’s groundwater supply, Fort Huachuca, delivering a crushing blow to Sierra Vista.

The effects of increased pressure on water supplies are already visible in the San Pedro River basin. As growth continues, without a successful water importation scheme in place, flows in the San Pedro River could become completely unsustainable. Local and federal initiatives have begun to address unsustainable water use practices in this region through science-based, collaborative decisionmaking to meet a federally mandated deadline of sustainable yield by 2011. The San Pedro River basin illustrates how protecting socioeconomic and ecological benefits of freshwater systems challenges watershed managers and creates implications for ecosystem sustainability and prevailing governance norms. It also provides an excellent case study for evaluating the role of science in public participation processes.

Residents’ reliance on groundwater for their daily needs complicates balancing the interests of growing communities and surrounding wildlife in the San Pedro River basin. While the aquifer contains enough water for human use for an extended period of time, the San Pedro River and the wildlife and ecosystem that rely on it require continuous base flow—groundwater outflow into the river system—which is directly connected to the water table. Groundwater pumping draws down the aquifer, causing base flow to become intermittent or nonexistent and threatening plants and animals. Public acknowledgement that surface water and groundwater are linked and that changes in development policies are required to protect the river was the first step in addressing land-use and water management practices in the Sierra Vista subwatershed.

Demand for groundwater in arid and semi-arid regions of the world is expected to increase over time, not only in response to population pressures but also due to climate change. For the southwestern United States and subtropical regions worldwide, the Intergovernmental Panel on Climate Change (IPCC) projects a decrease in total precipitation as well as an increase in temperatures—both of which will add more stress to riparian systems. For example, the IPCC projects that by 2020, climate change–related water stress will affect between 75 and 250 million people in Africa. The IPCC also anticipates a decrease in available freshwater in central, south, east, and southeast Asia as its population increases. In recent years, portions of the southeastern United States have also faced severe drought, including states with high precipitation relative to Arizona, such as Georgia, Alabama, and Florida. Georgia has been forced to quickly develop and implement statewide drought and conservation plans, including the formation of water basin advisory committees to give a local perspective on resource management options. Humans as well as ecosystems will be greatly impacted. Efforts by groups such as the Upper San Pedro Partnership (USPP) can be helpful in providing lessons to these new initiatives.

The western United States has seen a proliferation in collaborative watershed partnerships over the last three decades. This trend has emerged in an era of mandated public participation via the Clean Water Act (1972), National Environmental Policy Act (1969), Endangered Species Act (1973), and others, and at the same time, shrinking government in terms of budgets for public land management, increased population, and competition for use of natural resources. Collaborative partnerships are now an integral aspect of rural watershed management in Arizona. The Rural Watershed Initiative, which commenced in 1999, is the state’s main policy framework for such endeavors.

While partnerships’ decisions can have significant ramifications for water management in rural areas, the dynamics influencing these partnerships are not well understood. Major water infrastructure decisions, such as those now being considered in the Upper San Pedro basin, often have unanticipated longer-term environmental and social impacts. The USPP, convened in 1998, is the oldest and most advanced of Arizona’s 17 watershed partnerships. Operating within the Sierra Vista subwatershed of the Upper San Pedro River basin in Cochise County, Arizona, the USPP has engaged in water management discussions within a complex sociopolitical environment. Ecology, population growth, politics, economics, and land-use issues all intersect in this portion of the Upper San Pedro basin, providing several lessons about collaborative management of water resources with implications beyond Arizona.